The association between febrile seizures and cognitive function in young adulthood was examined in a population-based study of Danish conscripts at Aarhus University Hospital, Denmark. Men with a history of epilepsy were excluded. Analysis of health-care databases found that 2.8% of 18,276 eligible conscripts had a record of hospitalization for febrile seizures. Prevalence of IQ scores in the bottom quartile (<37) was 25.3% and 27.6% for men with and without febrile seizures, respectively. Low IQ scores were slightly more prevalent in men born premature (30%), small for gestational age (32%), mother <20 years (36%), or parity >3 (33%). Adjusted prevalence ratios for having a group IQ score in the bottom quartile was 1.09 for men with febrile seizures and 1.08 for those without. The prevalence ratios according to age at febrile seizure onset were 1.38 for 3 months to <1 yr; 0.98 for 1 to 2 years; and 1.14 for 3 to 5 years. Except for men whose febrile seizures occurred before age 1 year, there was little evidence of low cognitive function associated with a history of febrile seizures. 
COMMENT. Decreased cognitive function in young adults with a history of febrile seizures before age 1 yr is previously unreported. In another Danish study, children with a febrile seizure early (< 1 yr) or late (> 3 yr) had a higher rate of epilepsy compared to children with onset between 1 and 3 years . Abnormal MRIs in 11.4% of children with first simple febrile seizures, reported in a NY-Presbyterian Hospital study, was also an unexpected finding, given the presumed benign nature of the febrile seizure (Ped Neur Briefs June 2008;22:47-48) . MRI is not usually recommended in children with simple febrile seizures, in accordance with AAP guidelines.